x-rays

X-rays are a form of electromagnetic radiation like light, but of higher energy, so they can move through the body to form an image. Structures that are dense (such as bone) will appear white and air will be black. Other structures will be shades of gray.

Veins are not normally seen in an x-ray. That is why the special dye is needed. The dye highlights the veins so they show up better on x-rays.

How the Test is Performed

This test is done in a hospital. You will lie on an x-ray table. Local anesthetic is used to numb the area where the dye is injected. You may ask for a calming medicine (sedative) if you are anxious about the test.

The health care provider places a needle into a vein, most often in the groin but occasionally in the neck. Next, a flexible tube called a catheter (which is the width of the tip of a pen) is inserted into the groin and moved through the vein until it reaches the vein in the kidney. A blood sample may be taken from each kidney. The contrast dye flows through this tube. X-rays are taken as the dye moves through the kidney veins.

This procedure is monitored by fluoroscopy, a type of x-ray that creates images on a TV screen.

Once the images are taken, the catheter is removed and a bandage is placed over the wound.

How to Prepare for the Test

You will be told to avoid food and drinks for about 8 hours before the test. Your doctor may tell you to stop taking aspirin or other blood thinners before the test. DO NOT stop taking any medicine without first talking to your doctor.

You will be asked to wear hospital clothing and to sign a consent form for the procedure. You will need to remove any jewelry from the area that is being studied.

How the Test will Feel

You will lie flat on the x-ray table. There is often a cushion but it is not as comfortable as a bed. You may feel a sting when the anesthesia medicine is given. You will not feel the dye. You may feel some pressure and discomfort as the catheter is positioned.

There may be mild tenderness and bruising at the site where the catheter was placed.

Why the Test is Performed

This test is not done very often anymore. It has largely been replaced by CT scan and MRI. In the past the test was used to measure levels of kidney hormones.

Rarely, the test may be used to detect
blood clots
,
tumors
, and vein problems. Its most common use today is as part of an exam to treat
varicose veins
of the testicles or ovaries.

Blood clots

Blood clots are clumps that occur when blood hardens from a liquid to a solid. A blood clot that forms inside one of your veins or arteries is calle...

Kidney tumor

Risks

Risks from this test may include:

Allergic reaction to the contrast dye

Bleeding

Blood clots

Injury to a vein

There is low-level radiation exposure. However, most experts feel that the risk of most x-rays is smaller than other risks we take every day. Pregnant women and children are more sensitive to the risks of the x-ray.